The 3 X CT1 All In One Multi Purpose Waterproof Sealant & Construction in black is a versatile and high-quality adhesive from the United Kingdom. Specifically designed for use in fish pond aquarium tanks for KOI, this sealant offers a reliable and long-lasting solution for various sealing and construction needs. With its waterproof properties and easy application, this product is perfect for both residential and industrial applications, making it a valuable tool for professionals and DIY enthusiasts alike.